1. Field
The present invention relates to DC-to-DC converters.
2. Background Information
DC-to-DC converters provide the capability to convert energy supplied by a power supply from one voltage and current level to another voltage and current level. Such circuits are widely employed in conjunction with computing platforms, such as personal computers, server nodes, laptop computers, and a variety of other computing systems. Such circuits are desirable because specifications for a processor typically employ lower voltages, such as 1xc2xd to 2xc2xd volts, and higher currents, such as reaching 50 to over 60 amps, that may change over a relatively wide range with a relatively high slew rate.
DC-to-DC converters are desirable for providing voltage regulation under these conditions for a variety of reasons. One reason is because such circuitry may be placed relatively close to the board components, resulting in the capability to provide low local voltage tolerances due to higher switching frequencies, single output topology, and a reduction in resistance from shorter electrical connections. State of the art topologies for DC-to-DC converters are typically energy efficient, reliable and cost effective when input voltages and output voltages have relatively close levels. However, maintaining efficiency in an environment employing a comparatively low voltage is typically costly due at least in part to the high currents employed to maintain the same amount of power while supplying a relatively low voltage. Likewise, isolation high frequency transformers may be employed, however, such transformers are also relatively expensive. A need, therefore, exists for a DC-to-DC converter that addresses cost efficiency while having the capability to convert over a range of voltages and/or currents.
Briefly, in accordance with one embodiment of the invention, a DC-to-DC converter having an input voltage and an output voltage, includes: a circuit topology such that, in operation, the input and output voltages have the same polarity, and that a magnitude of a ratio of the input voltage to the output voltage of the DC-to-DC converter is capable of being equal to, greater than, or less than one. The circuit topology is also such that a same at least one capacitor and alternative coils of a two-coil inductor are employed in a primary and a secondary circuit loop of the DC-to-DC converter. The primary and secondary circuit loops are not electrically isolated.
Briefly, in accordance with another embodiment of the invention, a circuit for converting from an input direct current (DC) voltage, VIN, to an output direct current (DC) voltage, VO, where VO and VIN have the same polarity, includes: an inductor coupled so as to have a primary loop circuit and a secondary loop circuit that respectively conduct current at different times during circuit operation. The primary and secondary loop circuits are not electrically isolated. The primary loop and secondary loop circuits are further coupled so that, during circuit operation, while the inductor is charging via current flow in the primary loop circuit, the voltage across the coils of the inductor is VIN, and while the inductor is discharging via current flow in the secondary loop circuit, the voltage across the coils of the inductor is VO.
Briefly, in accordance with still another embodiment of the invention, a method of converting from an input direct current (DC) voltage, VIN, to an output direct current (DC) voltage, VO, where VIN and VO have the same polarity, includes the following. Current is conducted through a primary and a secondary loop circuit at different times so as to charge and discharge an inductor, included in both circuit loops. While the inductor charges the voltage across its coils is VIN, and while the inductor discharges the voltage across its coils is VO.